Moorside site investigations approach final stages

Fugro staff undertaking onshore and offshore seismic surveys for NuGen at Moorside
Fugro staff undertaking onshore and offshore seismic surveys for NuGen at Moorside

Fugro are starting the final phase of their site characterisation work on behalf of NuGeneration Limited (NuGen) at their Moorside site, close to Sellafield, in West Cumbria. To facilitate the Moorside project, NuGen is undertaking a programme of works and studies to provide information on the Moorside site’s characteristics. The objectives are to carry out a geotechnical and geophysical campaign, providing sufficient geological and geotechnical information to inform the detailed design of foundations and ancillary structures and to determine tunnel alignments.

Moorside is one of the largest UK site investigations to be let as a single package. Under the contract, Fugro is carrying out onshore and offshore site characterisation involving geotechnical, hydrological, topographical, geophysical and geo-environmental data acquisition.

Site characterisation for NuGen’s Moorside project is one of the largest UK site investigations to be let as a single package
Site characterisation for NuGen’s Moorside project is one of the largest UK site investigations to be let as a single package

In addition to informing the design and layout of the Moorside site, data will support licensing, planning applications and other consents for the construction of the nuclear power station.

Work started in early December 2015 on the nearshore phase which comprised bathymetry surveys utilising Fugro’s geophysical vessels Fugro Seeker and the RV Valkyrie.

In early 2016 the Fugro Seeker returned to site to complete the survey and also undertake preparatory UXO clearance surveys for geotechnical borehole locations and seismic refraction lines. In April 2016 11 geotechnical boreholes were completed as was a deep seismic reflection survey. Further work included bathymetric surveys, and shallow seismic reflection and refraction surveys.

Preparation of wireline tools for downhole logging
Preparation of wireline tools for downhole logging

In addition to offshore activities, Fugro has undertaken a significant onshore drilling programme for Moorside which has utilised up to 18 rigs to drill 300 boreholes.

To reduce spoil, sonic drilling techniques have been employed to drill large diameter boreholes for the installation of pumping wells and to facilitate deep geophysical wireline logging. Additionally, some boreholes from the geotechnical programme have been reused to support 2D seismic reflection surveys.

Fugro will present data from the land-based and marine seismic surveys to provide a continuous, land-to-sea profile through the shallow transition zone (intertidal area) to help the design and construction of new infrastructure. Fugro’s data management system ‘Fugro Online’ is being used to facilitate the exchange of data and the QA/QC process between NuGen and Fugro throughout the project.

On-site sample storage and logging facility
On-site sample storage and logging facility

The site team has also undertaking trial pitting and in situ testing to determine viable locations for the storage of excavated spoil, which will be reused for landscaping. The land-based site characterisation will be supplemented by drilling and groundwater monitoring to support radiological screening undertaken by Amec Foster Wheeler.

As part of the contract, Fugro is implementing its largest programme to date of sample testing and analysis in the UK.

Fugro is due to complete the bulk of the site characterisation before the end of the year.